Devices such as thin-film devices or micro-electro-mechanical devices (also further referred to as MEMs) may have specific requirements to the environment in which they operate or in which they are stored. Thin-film devices are, for example, devices which are constituted of a plurality of stacked layers which together constitute an electrical circuit, an electro-optical element or an optical element. Such electrical circuits typically are miniaturized electrical circuits, also known as Integrated Circuits or in short ICs which comprise stacks of conductive, semi-conductive and insulating layers. The electro-optical elements comprise stacks which, for example, constitute a light emitting diode, an organic light emitting diode or a laser diode, and thus typically at least partially have an electrical circuit equivalent to a diode-circuit combined with a light emitting layer which may, for example, be constituted of an organic light emitting layer which results in an Organic Light Emitting Diode (further also referred to as OLED). Electro-optical elements may also comprise stacks which, for example, constitute a solar cell able to absorb electromagnetic radiation and convert the absorbed electromagnetic radiation into electrical power. Optical elements may comprise several optical layers which constitute an optical circuit comprising, for example, light guides and light gates. Such optical elements often may be designed to perform similar functions as Integrated Circuits and are often designed to replace Integrated circuits.
All of these thin-film devices and/or MEMs require some kind of sealing to protect the devices from environmental influences or to store these devices in a well defined environment. The quality of the seal often determines the operational life-time of the thin-film device. Especially when the thin-film device is, for example, a light emitting or light absorbing device, the sealing of the thin-film device is done preferably in a glass package to allow electromagnetic radiation to pass the glass package.
Such glass packages are known, for example, from the US patent application US 2004/0207314. In this patent application, a hermetically sealed glass package is described for sealing an OLED display. The glass package comprises a first substrate plate and a second substrate plate and a frit deposited onto the second substrate plate. The OLEDs are deposited on the first substrate plate. An irradiation source is then used to heat the frit which melts and form a hermetic seal that connects the first substrate plate to the second substrate to seal the OLEDs. The frit is glass that is doped with at least one transition metal and possibly a filler configured for lowering the coefficient of linear thermal expansion (further also referred to as CTE) of the frit such that when the irradiation source heats the frit, it softens and forms a bond.
A disadvantage of the known glass package devices is that they are relatively expensive.